User:Jouvencel
Control command based of quaternions
Files :
 stabilization_attitude_quat_int.c (.h)
 stabilization_attitude_ref_quat_int.c (.h)
 quat_setpoint_int.c (.h)
 Position in the autopilot structure
 Control structure
note : () number of decimals for integer calculus
 Comments
 "stab_att_sp_quat (15)" attitude to reach
 "stab_att_ref_accel(12)", "stab_att_ref_rate(16)","stab_att_ref_quat(15)" references défined by two order model
 stabilization_cmd[X] (X=ROLL, PITCH, YAW) commands défined by a feedforward part and feedback part, feedback part is based on PID
 quaternions define the orientation of rotorcraft,
 the error between the quat_sp and the quat_ref is computed by a quaternion product,
 the dot_quaternion is computed by the formula
 The second order model :
 Integrates accelerate to obtain "stab_att_ref_rate" by the Euler method
 Integrates rate to obtain "stab_att_ref_quat" by the Euler method
 The Euler method uses dt. Here dt is implicite and equal 1/512 or ,
 Determines the stab_att_ref_accel(12) by a second order with and . and are defined in airframe.xml.
 The second order
 Feedforward part
 Feedback part
 Comments
With the assumption of small variations so and so on for pitch and yaw, terms of second order are ignored :



